1. Field of Use
The present invention relates to data processing systems and in particular to systems which include cache memory stores.
2. Prior Art
In general, cache memory systems are required to provide the most recently updated version of the information being requested. In order to ensure that this is done, some prior art arrangements have the central processing unit associated therewith perform the necessary cache updating operations when a portion of the information being written into backing store is changed. Normally, this is done by setting an invalidity indication in the cache store directory for signalling when the directory indicates that the information being updated in backing store is also stored in cache. Thereafter, the central processing unit is required to "flush" obsolete information from the cache store so that it does not appear in cache store the next time the information specified by the directory address is accessed.
The above arrangements have been found to be quite time consuming particularly where such information is being altered by a number of sources or units. Also, such arrangements require additional circuits for performing the type of operations metioned.
Accordingly, it is a primary object of the present invention to provide an improved arrangement for updating information stored in cache store.
It is a further object of the present invention to provide a cache store which can be updated by any one of a number of sources or command modules.